1. Field of the Invention
The present invention relates, in general, to intravenous catheter insertion devices, and in particular pertains to a catheter needle tip protector and a safety mechanism which provides fail-safe protection for clinical personnel against the possibility of accidental punctures by a used IV cannular needle through automatic catheter needle tip protecting structure operative upon withdrawal of the cannular from a venipuncture the body of a patient.
In particular, pursuant to specific aspects of the invention, there is provided a catheter insertion device incorporating interlocking sequenced guarding members which are capable of being utilized in a considerable variety and types of catheter insertion devices. In essence, an important consideration which must be given to the aspect that there is a present safeguard in essentially a "fail-safe" arrangement, whereby the used cannula is fully retracted into its protective structure or housing prior to disengagement thereof from a catheter hub. Hereby, it has been noted that, upon occasion, needle stick of users of the device may be encountered in that the needle tip of the used cannula may still protrude to some extent, and resultingly pose a danger or hazard to clinical personnel or physicians using the catheter insertion device during separation of the cannula assembly from the catheter and its attached catheter hub. In numerous constructions and designs of catheter insertion devices, for example, such as the currently employed so-called Luer lock versions or sideport catheters, various techniques and structures are employed for separating retracted used cannulas and their associated housings and protective structures from the respective catheter and catheter hub portion, the former of which is still inserted in the venipuncture formed in the body of a patient and which is adapted to be connected to various other sources of parenteral fluids, blood, medications and the like during intravenous fluid supplying procedures, as is well known in the medical technology.
An important aspect of the invention resides in being able to ensure that the structure of the housing and telescopable sequencing guards for the used cannula or hollow needle which is being retracted will impart a clear indication as to the efficacy of full retraction of the cannula, thereby ensuring not only visual but also audible assurance of such protective procedures having been implemented during the catheter and cannula separation process, and prior to the effecting of the release of the housing or structure protectively containing the used cannula from the catheter hub.
Pursuant to a particular aspect of the invention, which may be applicable to various types of catheter insertion devices as described hereinbelow, there is provided a structure comprising interlocking sequenced guarding members whereby in a plurality of telescoping steps, the cannula, comprising the hollow needle, may be retracted into the guarding members in a step-by-step relationship as the guarding members are telescopingly extended relative to each other so as to ultimately provide a multiple locking system generating sequentially generated audible sounds or "clicks" informing clinical personnel operating the catheter device that the cannula has, in fact, been fully retracted and protectively locked in place, and consequently will no longer pose any physical danger or hazard to the user or clinical personnel, thereby enabling the completing of safe separation of the needle or cannula-housing structure from the catheter hub.
The utilization of clinical apparatus in which pointed hollow needles or cannulas are employed in order to puncture the skin of a patient, and especially catheters utilizing such needles to effectuate venipunctures, is well known in the medical art and is widely practiced by physicians and clinical personnel for the purpose of injecting fluids and drugs directly into the bloodstream of patients. Additionally, during surgical operations or procedures it may be frequently required that whole blood transfusions and parenteral fluids be administered to a patient undergoing such surgical procedures. Basically, as is well known and has been employed for a considerable length of time, the introduction of such fluids into the cardiovascular systems of patients has necessitated the forming of a venipuncture utilizing a hollow rigid needle having a proximal attachment site for a fluid connection which is adapted to interconnect the needle with a source of intravenously administered fluids.
The foregoing method of administering fluids to patients through venipunctures has been subject to some rather serious problems in the administration of fluids to patients in this medical technology. Thus, a primary concern which had to be addressed resided in the inherent rigidity of the needle, the latter of which is normally generally constituted of surgical-quality steel, and while inserted into the vein of a patient, necessitated the needle to be maintained for reasons of safety in a fixed position at the general site of the venipuncture throughout the duration of fluid administration or transfusion, whereby such a procedure could conceivably consume a considerable length of time. In addition to the foregoing, at times it has been necessary to periodically draw blood samples and/or successively administer intravenous fluids to a patient, thus requiring the patient to be subjected to a series or plurality of venipunctures, each administered at a specific time and at different sites on the body, resulting in a relatively traumatic experience to the patient in view of such repeated and somewhat painful and unpleasant venipunctures.
In order to ameliorate or possibly even eliminate the foregoing problems, in the medical technology it has been more recently the practice to introduce a flexible tubular catheter of a low-friction material, such as a silastic or Teflon into the vein of a patient and to permit the catheter tube to remain in such a position over lengthier periods of time for purposes of; for example, periodically administering fluids, including parenteral fluids, blood/plasma transfusions, medications in liquid form and also for the collection of blood samples and the like. In this manner, the previously encountered trauma, extravasation, and infiltration caused by repeated venipunctures have been largely avoided, and the danger and discomfort to a patient of leaving a rigid needle in the body for a prolonged period of time has been generally overcome. Thus, in order to position the distal end of such a flexible catheter tube within the body cavity of a patient, such as a vascular cavity or vein, there is normally employed a cannula or hollow sharp-tipped needle for the purpose of forming the venipuncture. Thereafter, the flexible catheter tube, which is telescopically and slidably coaxially mounted on the outer circumference of the cannula or hollow needle so as to extend sleeve-like thereabout is advanced along the length of the needle into the vein subsequent to the needle having formed the venipuncture. Thereafter, the needle is adapted to be withdrawn from the interior of the catheter tube, while permitting the latter to remain within the body of the patient at the site of the venipuncture, and the needle is suitably discarded.
Inasmuch as the needle which has been previously positioned in the body of the patient upon forming the venipuncture may have been exposed to infectious agents; for instance, such as a patient infected with the Acquired Immune Deficiency Syndrome (AIDS) which is frequently or practically always ultimately fatal in nature, or other dangerous infectious conditions such as hepatitis, there is present the danger or hazard that the clinical personnel may inadvertently or accidentally jab or stick themselves with the used needle after withdrawal from the body of the patient, with the possibility of infection or even death resulting therefrom.
2. Discussion of the Prior Art
Although extendable or telescoping elements for protecting used cannulas of catheter insertion devices are currently known in the art, none of these provide for the use of interlocking sequenced telescoping guarding-members for the "fail-safe" retraction and protection of the cannulas.
Thus, U.S. Pat. No. 4,950,252 to Luther et al. discloses a cannula guard and housing structure which are mutually relatively axially extendable for receiving therein a used cannula in a protective environment.
McDonald U.S. Pat. No. 4,944,725 addresses the problem in disclosing an intravenous catheter which incorporates a structure for protecting a clinician or physician from accidental puncture which may result in the transfer of dangerous infections from the patient. The catheter is introduced into the patient's body with the aid of a needle of hollow or cannula construction which is thereafter withdrawn from the patient's body into a protective housing in the absence of exposing the needle during any intermediate stage of the withdrawing process. The housing is then latched in place subsequent to needle withdrawal, and for unlocking a catheter hub in place subsequent to the time, and effecting withdrawal and locking in one continuous motion.
Another publication which is applicable to providing for the protection of the point of a needle subsequent or upon removal thereof from the body of a patient is disclosed in Dombrowski et al. U.S. Pat. No. 4,790,828, wherein a nose portion or cap is tethered to a housing by means of a collapsible tethering structure encompassing the needle such that the needle will be retracted into a sheath-like expanding arrangement which will securely prevent potential injury to clinical personnel caused by being jabbed by an exposed used point of a needle.